The present invention relates generally to surgical instruments, and more particularly to surgical retractor, instrument mount, and tissue stabilizer devices for use during coronary artery bypass graft surgery.
Diseases of the cardiovascular system affect millions of people each year and are a leading cause of death throughout the world. The cost to society from such diseases is enormous both in terms of the number of lives lost as well as in terms of the costs associated with treating patients through traditional surgical techniques. A particularly prevalent form of cardiovascular disease is a reduction in the blood supply leading to the heart caused by atherosclerosis or other condition that creates a restriction in blood flow at a critical point in the cardiovascular system that supplies blood to the heart.
Treatment of such a blockage or restriction in the blood flow leading to the heart is, in many cases, treated by a surgical procedure known as a coronary artery bypass graft (CABG) procedure, more commonly known as a xe2x80x9cheart bypassxe2x80x9d operation. In the CABG procedure, the surgeon xe2x80x9cbypassesxe2x80x9d the obstruction to restore normal blood flow to the heart either by attaching an available source vessel to the obstructed target coronary artery or by removing a portion of a vein or artery from another part of the body, to use as a graft, and installing the graft between a point on a source vessel and a point on a target artery.
To restore the flow of blood to the heart, the CABG procedure requires that a fluid connection be established between two vessels. This procedure is known as an xe2x80x9canastomosis.xe2x80x9d Typically, a source vessel, such as a source artery with an unobstructed blood flow, i.e., the left internal mammary artery (LIMA), or a bypass-graft having one end sewn to an unobstructed blood source such as the aorta, is sewn to a target occluded coronary artery, such as the left anterior descending (LAD) artery or other vessel, that provides blood flow to the muscles of the heart.
Although the CABG procedure has become relatively common, the procedure itself is lengthy and traumatic and can damage the heart, the cardiovascular system, the central nervous system, and the blood supply itself. In a conventional CABG procedure, the surgeon makes an incision down the center of the chest, cuts through the sternum, performs several other procedures necessary to attach the patient to a heart-lung bypass machine, cuts off the blood flow to the heart, and then stops the heart from beating in order to complete the bypass. The most lengthy and traumatic surgical procedures are necessary, in part, to connect the patient to a cardiopulmonary bypass (CPB) machine to continue the circulation of oxygenated blood to the rest of the body while the bypass is completed.
In recent years, a growing number of surgeons have begun performing CABG procedures using surgical techniques especially developed so that the CABG procedure could be performed while the heart is still beating. In such procedures, there is no need for any form of cardiopulmonary bypass, no need to perform the extensive surgical procedures necessary to connect the patient to a cardiopulmonary bypass machine, and no need to stop the heart. As a result, these beating heart procedures are much less invasive and the entire procedure can typically be achieved through a small number, typically one or two, comparatively small incisions in the chest.
Despite the advantages, the beating-heart CABG procedure is not universally practiced, at least in part, because of the difficulty in performing the necessary surgical procedures using conventional surgical instruments. For example, it has been difficult for the surgeon to access the required areas of the heart requiring revascularization. In addition, the various surgical steps that are required to be performed on the heart itself are more difficult to perform because the heart muscle continues to move and contract to pump blood throughout the duration of the procedure.
The specific portion of the surgical procedure that creates the anastomosis in the beating-heart CABG procedure is particularly difficult. Completion of the anastomosis requires placing a series of sutures through extremely small vessels on the surface of the heart while the heart muscle continues to beat. Moreover, the sutures must be carefully placed to ensure that the source vessel or graft is firmly attached and will not leak when blood flow through the vessel is established. In cases where the target coronary artery is temporarily obstructed, for example, to improve the surgeon""s visibility and avoid excessive blood loss, it is also important that the anastomosis procedure be performed rapidly to avoid ischemic damage to the heart.
Further adding to the difficulty of the procedure is the fact that the working space and visual access are often quite limited. The surgeon may be working through a small incision in the chest, for example, or may be viewing the procedure on a video monitor if the site of the surgery is viewed via surgical scope. The vessel, and particularly the arteriotomy to which a source vessel is to be anastomosed, may also be very difficult for the surgeon to see as it may be obscured more or less by layers of fat or other tissue.
The beating-heart CABG procedure could be greatly improved if the heart could be accessed and stabilized during the procedure such that the motion of the heart, particularly at the site of the anastomosis, is minimized even though the heart continues to beat and supply blood to the body. The beating-heart CABG procedure could be further improved if the target vessel, and specifically the arteriotomy was presented to the surgeon in a way that allows sutures to be easily placed.
In view of the foregoing, it would be desirable to have improved devices for accessing and effectively stabilizing the beating heart at the site of the anastomosis. It would be desirable to have a retractor system that provides unobstructed and organized access to the areas of the heart requiring revascularization. It would be further desirable to have a low-profile, atraumatic stabilizing device that stabilizes the beating heart at the site of the anastomosis and provides a favorable presentation of the target vessel and the arteriotomy. It would be further desirable to provide a mount for the stabilizing device, or other instruments, that allows the stabilizing device to be easily maneuvered to the desired position and orientation, fixedly secured until the procedure is completed, and then easily removed from the site of the anastomosis.
The present invention will be described for use in performing CABG surgery, but the invention is not limited thereto, and is contemplated to be useful for other surgical procedures requiring access through an incision into a patient.
The present invention involves various aspects of a surgical retractor for use, for example, in performing a CABG procedure on a beating heart. The present invention may involve a surgical retractor which facilitates the creation of a working opening through an incision in a patient, such as a sternotomy. The surgical retractor may also provide a platform for securely mounting various instruments or for organizing such things as sutures. The present invention may also include an instrument mount which may be secured to the platform.
One aspect of the present invention involves a surgical retractor system for creating an opening through an incision in a patient which includes a drive mechanism and one or more retractor blades detachably mounted to the drive mechanism. The drive mechanism may have a first housing and a second housing, the first housing being moveable relative to the second housing. In a preferred embodiment, the housings are associated with a toothed bar which provides a means for driving one housing relative to the other.
The surgical retractor system preferably has first and second retractor blades each having a first end, a second end, and a retractor body extending therebetween. The first ends of the first and second retractor blades are preferably detachably mounted, coupled, or otherwise attached to the first and second housings, respectively. The first and second retractor blades preferably have at least one channel adapted to receive opposite sides of the incision. Preferably, the channel or channels are adapted to receive opposite sides of a severed or incised sternum.
The surgical retractor system may also include an elongate rail oriented along at least a portion of a length of at least one of the retractor bodies. Preferably, each retractor blade has a rail that extends substantially from end to end of the length of the retractor. The rail may be a channel formed within the retractor body or may extend outwardly from the retractor body. The rail may be substantially straight along its length or may be curved along its length.
Preferably, the rail extends outwardly from the retractor body and has a top section adapted to engage a separate mount. In one embodiment, the rail has a top portion and a bottom portion, the bottom portion having a narrowed region adjacent the top portion and forming first and second tabs on the top portion. Most preferably, the rail has a T-shaped cross-section.
The surgical retractor system may further comprise a plurality of suture holders, preferably associated with the rail. The rail may include a plurality of open slots, transverse to said rail, for receiving one or more sutures. The open slots may include a means for locking the sutures within the open slots. In one embodiment, the open slots have a first slot section which bifurcate into a second slot section and a third slot section. Each of the second and third slot sections may have a means for locking sutures within the second and third slots respectively. In a preferred embodiment, open slots have a depth that allows the sutures to be positioned below the top section of the rail.
The surgical retractor system may also provide features that allow the retractor blades to be securely mounted to the drive mechanism. The first and second housings may have at least one pin extending therefrom and each of the first and second retractor blades have a mating hole formed therein for receiving the pins when the first and second retractor blades are attached to the first and second housings. Preferably, the pins may be cylindrical or tapered.
The present invention may also involve a surgical retractor system for creating an opening through an incision in a patient which includes a drive mechanism having a first retractor blade and a second retractor blade attached thereto. The blades are preferably substantially parallel to each other and adapted to engage opposite sides of the incision. Preferably, the blades being moveable relative to one another. At least one of the blades has a rail extending upwardly from it with at least one open slots for receiving one or more sutures therein. The rail may have a top section adapted to engage a separate mount. Preferably, the rail has a T-shaped cross-section and may be curved or straight along its length.
The surgical retractor system may have at least one open slot transverse to the rail, the open slot having a depth which allows one or more sutures to be positioned completely below the top section. Preferably the open slot has an internal wall and the surgical retractor system further comprises a suture locking member. The suture locking member includes a body having a fixed end and a free end, the free end engaging the internal wall so as to clamp a suture placed between the free end and the internal wall. The body may be flexible or substantially rigid and pivotable about the fixed end. The body may be at an acute angle relative to the open slot.
In another aspect, the present invention involves a surgical retractor for use in operating on a heart and includes a drive mechanism having one or more retractor blades having an open suture channel or slot having a pivoting suture lock. In one embodiment the surgical retractor includes a drive mechanism having a first retractor blade and a second retractor blade in an opposing relationship for engaging opposite sides of an incision made within the thoracic cavity. The first retractor blade is typically moveable relative to the second retractor blade to create a widened opening through the incision. At least one of the retractor blades preferably has an open slot for receiving a suture.
The surgical retractor preferably has a suture locking member having a body with a fixed end and a free end, the body being pivotable about the fixed end so as to urge the free end against an internal wall of the open slot. The body generally has a central axis extending from the free end to the fixed end, the central axis of the body being at an angle of less than 90 degrees with the open slot. More preferably, the body is at an angle of more than about 65 degrees and less than about 90 degrees. In a preferred embodiment, the free end has a number of ridges formed therein. Preferably, at least a potion of the fixed end is substantially cylindrical and the surgical retractor may include a mating cylindrical cavity or recess.
These and other features of the present invention will become more fully apparent from the following description and appended claims.